Westermo MRD-310, Reference Manual

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7.2.2 Packet framer settings
The packet framer is available for all port functions that
carry raw data (these settings are not available for the DNP3
IP-Serial Gateway or Modbus IP-Serial Gateway). The packet
framer allows data received from the serial port to be pack-
etised into larger blocks, reducing the overhead incurred when
repeated packets of small sizes are sent over the network.
Figure 118: Packet framing configuration options
The following options control the packet framer:
Maximum packet size
This value determines the largest packet size to be passed to
the network for transmission. If set to 0, the packet framer
will be disabled and data will bypass the packet framer. The
value chosen will depend on the application, however, the
value should not be set higher than 1024, so the packet will fit
a conventional Ethernet frame.
Minimum size before sending
In some applications, it may not be desirable to wait for the
exact number of bytes specified in Maximum packet size
before sending the packet. The value set in this field, which
must be less than or equal to the Maximum packet size, acts
as a send threshold. Once the accumulated byte count reaches
this value, the packet will be sent.